Manifold silencer with circular flow



April 26, 1949. T'YSKEAWICZ 2,468,384

MANIFOLD SILENCER WITH CIRCULAR FLOW Filed March so, 1945 INVENTORJOHN/7 T J/rEW/c BY g ATTORNEYS Patented Apr. 26, 1949 UNITED STATESPATENT OFFICE MANIFOLD SILENCER WITH CIRCULAR FLOW Application March 30,1945, Serial No. 585,590

6 Claims.

The present invention relates to silencing devices adapted to beinstalled directly on the exhaust ports of internal combustion enginesso as to combine the functions of a gas collecting manifold such as isusually found on multi-cylinder engines with that of an effectivesilencer. Such devices are of particular application to railwaylocomotives where the space available for silencing equipment is aminimum.

As is well known in the art, it is extremely difficult to obtain asatisfactory degree of silencing with a device limited to a singlechamber. Attempts to incorporate a two chamber device in space generallyallotted for silencing on a locomotive has resulted in the creation oftoo high a back pressure. This effect is augmented by the fact thatthere is little chance for cooling of the exhaust gases between thecylinder and the closely adjacent silencing manifold and consequentlythe temperature remains high with proportionately high gas velocities.

It is a feature of the present invention that the back pressure of themultichambered device shown is of the same order as that usuallyobtained with single chambered manifold silencers while the soundattenuation is considerably greater. The invention accomplishes thispurpose by providing a path for the gases which, while the noiseproducing surges are broken up, permit the gases to flow without anyabrupt changes in direction, the gases entering the casing tangentiallyand persisting in the same sense of rotation until they are dischargefrom the silencer.

For a complete description of the invention reference is made to thedrawings in which Fig. 1 is a side elevation, with the casing brokenaway to the median plane, of one embodiment of the invention;

Fig. 2 is a transverse section on line 2 -2 of Fig. 1;

Fig. 3 is a side elevation, with the casing broken away to the medianplane, of another embodiment of the invention;

Fig. 4 is a side elevation, with the casin broken away to the medianplane, showing the application of certain principles of the invention toa silencer of other than the manifold type;

Fig. 5 is a section on line 5-5 of Fig. l; and

Fig. 6 is a detail of a further modification.

Referring to Fig. 1, it will be seen that this emi bodiment is adaptedto serve two cylinders. It comprises a cylindrical shell H closed by endheaders l2, l3, and having a pair of intermediate transverse headers l4,l5 dividing the interior of the silencer into two separate inletchambers l6,

ll, into which the exhaust gases flow through tangentially disposed,slotted inlet pipes l8, l9, respectively. The gases are thus given awhirling motion within chambers l6 and H. An outlet chamber 20 ispositioned between the inlet chambers. Since the spacing of these inletpipes is determined by the engine ports, which are generally closetogether, it is desirable to position the intermediate headers I 4, l5close to these inlet pipes in order to increase the size of the outletchamber and thus to secure as good a balance as possible between thevolumes of the two inlet chambers and the outlet chamber 20 defined bythe casing II and headers I4, I53.

The whirling gases in the inlet chambers I6, I! are conducted into theoutlet chamber 20 through intermediate, angularly disposed tubes 2 I, 22pref erably provided with anti-resonance perforations 23. For adisclosure of such anti-resonating constructions reference is made tothe patent to Bourne, 2,297,046, September 29, 1942, in which the propersizes and spacing of the anti-resonance holes are fully described. Theseintermediate tubes are located near one side of the casing and projectinto their respective inlet chambers at an angle E with the axis of thesilencer of preferably from 30 to degrees. I have found that thisarrangement yields the lowest backpressure because the exhaust gases inthe inlet chamber partake of a spiral motion and by disposing theintermediate tubes as described the gases enter them with a minimumchange in direction. Since the outlet chamber 20 is ordinarilyrelatively short in longitudinal extent, due to limitations of enginedesign, it is expedient to terminate the intermediate conduits 2| 22within it close to the intermediate headers in order to avoid undueinterference with smooth gas flow in the outlet chamber.

In order to provide somewhat more effective volume for the inletchambers as seen from their respective engine cylinders; that is to say,in order to make available the volume of both inlet chambers to eitherinlet, I provide an equalizing conduit 24, extendin from the interior ofone inlet chamber to the interior of the other. This conduit is axiallydisposed and projects an appreciable distance into the chambers from thintermediate headers. It is preferably fitted with anti-resonanceperforations 25, 25 in the inlet chamber portion and with a relativelysmall aperture 2'! opening into the outlet chamber 20. This equalizingconduit does not function as a primary gas passage but serves tointroduce into each of the inlet chambers an acoustic reactance wherebyany natural resonances which may exist are damped. In addition, heavysurges introduced into either inlet chamber are partly bled oil throughthe conduit 2 into the other inlet chamher, since the pressureconditions in the two chambers are out or phase with each other due tothe fact that both engine cylinders involved do not fire at the sameinstant. A tangential outlet conduit 253, preferably provided with anarrow longitudinal slot 28, is positioned to conduct the whirlingexhaust gases from the periphery of the outlet chamber to atmosphere.The inner end of this conduit is seen to point in a direction to pick upthe whirling gases in this chamber, this whirling motion beingperpetuated in the outlet chamber by the angularly disposed inntermediate conduits 2!, 22.

Fig. 3 shows an arrangement adapted for use with a four cylinder engine.In this case the casing 3% is divided by partitions 3 l, 32, 33 and 34and provided with end headers 35 and 36 to form three inlet chambers 37,38 and 39 and two outlet chambers 4B and ll. The inlet pipes 42, 43, 44and 45 enter tangentially and are constructed to fit the manifolds ofthe particular engine to which the silencer is to be applied. Theirdetail is therefore unimportant and the pipes have been showndiagrammatically. The remaining construction is generally similar tothat shown in Fig. 1 and only the differences will be emphasized. Thetwo central inlet pipes 43 and 44 enter a single chamber 38approximately twice the size of each end inlet chamber. The slantingtransfer conduits 46, 47, 48 and 48 are here shown as arranged at anangle of 35 to a horizontal plane including the axis of the silencer,and each has an anti-resonance hole at its center lying within the inletchamber and an anti-resonance hole 5! at its quarter point lying withinthe outlet chamber. The equalizing conduit 52 has a single hole 53,preferably positioned at the side of the pipe remote from the transferconduits, and is provided at each end with a slot 54 lying wholly withinthe respective inlet chamber. The two exhaust pipes 55 and 53 aretangentially arranged in the same manner as shown in Fig. 2 and areprovided with slots 57 within the exhaust chamber.

Figs, 4 and 5 show an adaptation of certain principles of the inventionto a silencer having one inlet connection '58 leading into the inletchamber Bi, and one outlet connection 62 for conducting the whirling gasout of the outlet chamber 53. The intermediate transverse partition B lis pierced by a transfer conduit 65 having anti-resonating holes andserving to conduct the gases from chamber 6! to chamber 63. Thisembodiment is particularly useful where extremely low backpressure isdesired and where installation conditions permit its use. Allalternative arrangement for the inlet pipe to the silencer is depictedin Fig. 6 wherein the inlet conduit 67 is shown arranged in the samevertical plane as the outlet conduit E53.

In order to further improve the silencing action in devices of thistype, I preferably proportion the lengths of the inlet and outletchambers so that they do not bear an integral relation one with theother. For instance I may make the lengths of these chambers in theratio of 7:3 or 7:2 in the case of the embodiments shown in Figs. 1 to3. For the device of Figs. 4 and 5 I prefer to make them in the ratio of7:5. Thus, any important longitudinal resonances which might exist inone chamber are not reinforced in the other.

I claim:

l. A silencer comprising walls defining a generally cylindrical inletchamber and a generally cylindrical outlet chamber axially alignedtherewith and adjacent thereto, an inlet conduit having an open endprojecting into the inlet chamber transversely to the axis of thechamber and substantially tangentially thereof and at the side of theinlet chamber adjacent to the outlet chamber, whereby gases entering theinlet chamber through the inlet conduit will be given a whirling motionabout the axis of the casing, an outlet conduit having an open endprojecting into the outlet chamber transversely to the axis of thechamber and substantially tangentially thereof and at the side of theoutlet chamber adjacent to the inlet chamber and facing oppositely tothe inlet conduit in relation to the circumference of the cham ber,whereby gases whirling in the sense imparted by the inlet conduit willbe picked up by the open end of the outlet conduit without reversal ofgas flow, and an open ended intermediate conduit passing through thatportion of the walls separating the inlet and outlet chambers at oneside of the axis of the casing and extending lengthwise of the casingwith its ends displaced circumferentially in such directions that itsopenings into the inlet and outlet chambers are directed oppositely tothe open ends of the inlet and outlet conduits respectively in relationto the circumferences of said chambers, whereby gas will be transferredby the intermediate conduit from one chamber to the other withoutreversal of its direction of whirl.

2. A silencer comprising a generally cylindrical casing, a transverseheader dividing the easing into an inlet chamber and an outlet chamber,an inlet conduit projecting into the inlet chamber transversely to theaxis of the chamber and substantially tangentially thereof, wherebygases entering the inlet chamber through the inlet conduit will be givena whirling motion about the axis of the casing, an outlet conduitprojecting into the outlet chamber transversely to the axis of thechamber and substantially tangentially thereof and facing oppositely tothe inlet conduit in relation to the circumference of the casing,whereby gases whirling in the sense imparted by the inlet conduit willbe picked up by the outlet conduit without reversal of gas flow, and anopen ended intermediate conduit passing through the transverse header atone side of the axis of the casing and extending lengthwise of thecasing with its ends displaced circumferentially in such directions thatits openings into the inlet and outlet chambers are directed oppositelyto the open ends of the inlet and outlet conduits respectively inrelation to the circumference of the casing, whereby gases will betransferred by the intermediate conduit from one chamber to the otherwithout reversal of its direction of whirl.

3. A silencer comprising walls defining a pair of generally cylindricaland axially aligned inlet chambers and a generally cylindrical outletchamber located between and in axial alignment with them, a pair ofinlet conduits having open ends projecting in the same direction intothe inlet chambers transversely to the axis of the chamber andsubstantially tangentially thereof, whereby gases entering the inletchambers through the inlet conduits will be given a whirling motion inthe same sense in both said inlet chambers, an outlet conduit having anopen end projecting into the outlet chamber transversely to the axis ofthe chamber and substantially tangentially thereof and facing oppositelyto the inlet conduits in relation to the circumference of the chamber,whereby gases whirling in the sense imparted by the inlet conduits willbe picked up by the open end of the outlet conduit without reversal ofgas flow, and open ended intermediate conduits passing through thatportion of the Walls separating the inlet and outlet chambers at oneside of the axis of the casing and extending lengthwise of the casingwith its ends displaced circumferentially in such directions that theiropenings into the inlet and outlet chambers are directed oppositely tothe open ends of the inlet and outlet conduits respectively in relationto the circumferences of said chambers, whereby gas will be transferredby the intermediate conduits from the inlet chambers to the outletchamber without reversal of its direction of whirl.

4. A silencer comprising walls defining a pair of generally cylindricaland axially aligned inlet chambers .and a generally cylindrical outletchamber located between and in axial alignment with them, a pair ofinlet conduits having open ends projecting in the same direction intothe inlet chambers transversely to the axis of the chamber andsubstantially tangentially thereof, whereby gases entering the inletchambers through the inlet conduits will be given a whirling motion inthe same sense in both said inlet chambers, an outlet conduit havin anopen end projecting into the outlet chamber transversely to the axis ofthe chamber and substantially tangentially thereof and facing oppositelyto the inlet conduits in relation to the circumference of the chamber,whereby gases whirling in the sense imparted by the inlet conduits willbe picked up by the open end of the outlet conduit without reversal ofgas flow, open ended intermediate conduits passing through that portionof the walls separating the inlet and outlet chambers at one side of theaxis of the casing and extending lengthwise of the casing with its endsdisplaced circumferentially in such directions that their openings intothe inlet and outlet chambers are directed oppositely to the open endsof the inlet and outlet conduits respectively in relation to thecircumferences of said chambers, whereby gas will be transferred by theintermediate conduits from the inlet chambers to the outlet chamberwithout reversal of its direction of whirl, and a conduit passingthrough the outlet chamber and having an open end Within each inletchamber.

5. A silencer comprising a generally cylindrical casin a transverseheader dividin the casing into an inlet chamber and an outlet chamber,an inlet conduit projecting into the inlet chamber transversely to theaxis of the chamber and substantially tangentially thereof at a pointadjacent the header, an intermediate conduit projecting into said inletchamber and passing through the header into the outlet chamber at apoint removed from the center of the header and making an angle of from30 to 50 degrees 'with a plane passing through the axis of the casing,the open ends of said conduit bein in adjacency to the cylindrical wallsof the chambers, and an outlet conduit projecting into the interior ofsaid outlet chamber transversely to the axis of the chamber andsubstantially tangentially thereof and positioned in' adjacency to theheader with its open end. disposed oppositely to the inlet conduit withrelation to the circumference of the casing, whereby gases passingthrough the silencer acquire and maintain a whirling motion in the samesense in both the inlet and the outlet chambers and suffer no reversalof flow in their passage through the silencer.

6. A silencer as claimed in claim 5, wherein the inlet and outletconduits are so positioned that planes passing through the longitudinalaxis of each of said conduits parallel to the axis of the casing are atsubstantially right angles to each other.

JOHN P. TYSKEWICZ.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,294,475 Kirkham Feb. 18, 19192,034,119 Shebat Mai. 17, 1936 2,264,195 Bourne Nov. 25, 1941 FOREIGNPATENTS Number Country Date 432,372 Great Britain July 25, 1935

